bex report

Hi, i have to create one bex report from SD module with below fields:

contract | valid-frm | valid-to | amount | sub-contract | valid-frm | valid-to | amount | sales order | valid-frm | valid-to | amount | invoice doc | amount |

here, i have all the data from datasources. but thr problem is in creating such format. i have used infoset.

the data in datasource is like this :

doc no   dates   reference doc

------------------------------------------

contract1          -

sub-contract     contract1

sales order1     sub-contract1

invoice1           sales order1

invoice2           sales order1

but sub-contract is optional one , so the data could be like this :

doc no   dates   reference doc

------------------------------------------

contract1          -

sales order1     contract1

invoice1           sales order1

invoice2           sales order1

i have created the repor basis on first logic but the second logic's data is not comng because it is skipping the second level

can you plase tell me any other way of creating such report.

can we apply some condition in infoset.